But when Evon Hekkala of Fordham University in New York City and colleagues took DNA samples from museum specimens of the Vegas Valley frogs, they found they were indistinguishable from Chiricahua leopard frogs living 400 kilometres away in central Arizona. A second population of the Chiricahua frogs, further south-east, may be a separate species (Conservation Genetics, DOI&colon; 10.1007/s10592-011-0229-6).

Museum specimens of the extinct frog are genetically indistinguishable from a species living in Arizona

Advertisement

The Chiricahua frogs are themselves vulnerable, as their population has fallen 30 per cent in three generations. They are worse off than we thought. “A threatened species is now divided in two,” Hekkala says.

The rediscovery of the Vegas Valley frogs poses a dilemma, says the paper’s co-author Raymond Saumure, of the Las Vegas Springs Preserve. Saumure is helping to restore the wetlands of the Las Vegas Creek, where the frogs once lived. The plan was to populate it with the severely threatened relict leopard frog (L. onca), but it may make more sense to reintroduce Vegas Valley leopard frogs. “It’s a tough call,” Saumure says.